The SUNY/HSCB site proposes to recruit approximately 50 pregnant HIV infected women per year into the WITS. Our site has a track record going back fifteen years of identifying, recruiting and retaining such a population into longitudinal studies. Four senior researchers, Drs. Landesman, Handelsman, Minkoff and Hittelman, who together have 60 years of experience in HIV cohort studies, direct our program. Our site, invited into the WITS in 1991, has averaged 46 new study entrants per year. Enrolled women who deliver have a retention rate of 92% at 6 months and 87% at the one-year time point, which is the time they would complete the study in the WITS4 protocol. Of children old enough, 97% continued on study long enough to determine their HIV status. Of these children, 94% of those eligible continue through 1 year and 94 % of these children continue through 2 years. Averaging 922 visits per year, we have missed only 11 percent of study visits and have submitted 99 % of expected forms. Our site has an extensive array of 21 integrated research and service programs which serve the needs of over 2,000 HIV infected patients. The extensive linkages within the community and with other hospitals allow us to easily recruit from the 275 to 300 HIV infected pregnant women giving birth in Brooklyn each year. The SUNY/HSCB site has arranged for all virology/immunology work to be performed at Dr. Jane Pitt?s laboratory at the Columbia Presbyterian WITS site. Dr. Pitt?s laboratory has an outstanding record in performing WITS required assays and is ACTG certified. Scientifically, Drs. Landesman, Handelsman, Minkoff and Hittelman are widely published in the field of perinatal HIV disease. Dr. Landesman was the first author on the 1996 WITS paper "Obstetrical factors and the transmission of Human Immunodeficiency virus type 1 from mother to Child". Dr. Minkoff is the premier obstetrician in the country for women with HIV disease. Both Drs. Handelsman and Minkoff served on the New York State AIDS Institute Committee on Perinatal Transmission. Dr. Handelsman served as a special advisor to the US Food and Drug Administration in the area of perinatal transmission.